These hooks are specially intended for the use with a J-rail or Galerie Rail. Such a rail is particularly interesting for exhibitions and exhibitions because the piece of art can be hung up and replaced very easily from the ground.
With other rail systems, a stepladder or chair has to be used to re-hang wires and hooks in the rail and to swing them out of the rail. The hooks shown themselves usually have a hook or clip form.
You will see the load bearing capacity for each part to indicate which hook best fits the weight of the object or objects that you want to hang.